Teleseismic tomography of the southern Puna plateau in Argentina and adjacent regions

Abstract

An array of 74 seismological stations was deployed in the Argentine Puna and adjacent regions for a period of two years. The aim is to investigate the seismic structure in the crust and upper mantle in order to address fundamental questions regarding the processes that form, modify and destroy continental lithosphere and control lithospheric dynamics in this part of the Central Andes. This portion of the Central Andes is an ideal locale to address these questions given that there is geologic evidence that there has been recent lower crustal and mantle lithospheric delamination. 2We performed a teleseismic P wave tomography study using seismic events at both teleseismic

Subduction Zone Tomography

“…3.2,3.3,3.4,3.5,3.7,3.8,3.9,3.10,3.11,3.12 and 3.13). This seismological feature has been found in all subduction zones which have been studied using seismic tomography (e.g., Zhao et al 1992Zhao et al , 1995Zhao et al , 2000Hasegawa and Zhao 1994;Ma et al 1996;Nakajima et al 2001;McNamara and Pasyanos 2002;Nakamura et al 2003Nakamura et al , 2008Wagner et al 2005Wagner et al , 2010Zhao 2005, 2006a, b;Katsumata et al 2006;Matsubara et al 2008;Wiens et al 2008;van Stiphout et al 2009;Schmandt and Humphreys 2010;Huang et al 2011a;Bianchi et al 2013;Liu et al 2013a, b, and many other references mentioned in this and the following sections). This seismic feature is also consistent with the petrologic results (e.g., Tatsumi 1989;Peacock 1990;Iwamori and Zhao 2000;Hacker et al 2003), indicating that arc magmatism and volcanism are caused by the joint effects of fluids from slab dehydration and corner flow in the mantle wedge.…”

Thermal and geodynamic contributions to the elevation of the Altiplano–Puna plateau

“…One of such faults, the NW-SE trending Olacapato-Toro Lineament separates the northern Puna (between $22°and 24°S) from the southern Puna (between $24°a nd 28°S); (Bianchi et al, 2013). Conspicuous differences between the northern and southern Puna plateau were previously noted by several authors (e.g.…”

“…Due to significant differences along the plateau, it is divided in the Altiplano (north of 22°S) and the Puna (south of 22°S) (Bianchi et al, 2013). The Puna plateau has an average altitude of $4.2 km above sea level, being approximately 1 km higher than the Altiplano plateau ($3.2 km).…”

“…These authors proposed that the ongoing uplift and peripheral subsidence (''sombrero uplift'') would result from ballooning of a large mid-crustal diapir fed by hot low-viscosity material from the Altiplano-northern Puna Magma Body. Recently, Bianchi et al (2013) performed a teleseismic P-wave tomography study in the southern Puna. They identified a prominent low-velocity body located in the crust between 26-27.5°S.…”

“…Bianchi et al (2013) related the detected velocity anomalies with a mid-crustal back-arc melt zone under the southern Puna: the Southern Puna Magma Body (SPMB). The SPMB could be disconnected from the Altiplano-northern Puna Magma Body (Yuan et al, 2000) and the limit between them could be related to the Olacapato-Toro Lineament (Bianchi et al, 2013).…”